CORONOR Registry: No Advantage to Prolonged DAPT in Stable CAD

About one-quarter of patients with stable coronary artery
disease (CAD) are prescribed dual antiplatelet therapy (DAPT), probably due to
factors such as MI or revascularization within recent years,
diffuse atherosclerosis, and DES implantation,according to a registry studypublished online June 23, 2014, ahead of print in the American Heart Journal. Nonetheless,
these patients are no more likely to be protected against future ischemic
events than those receiving aspirin or clopidogrel alone.

Methods

Investigators led by Gilles Lemesle, MD, of the Centre Hospitalier Régional et Universitaire de Lille (Lille, France), looked at the prevalence and correlates of prolonged DAPT in 3,691 French patients with stable CAD enrolled in the prospective CORONOR registry between February 2010 and April 2011. Patients were eligible if they had an MI or revascularization more than 1 year prior (but not within 1 year) or an obstruction of at least 50% in 1 native vessel. Those on chronic oral anticoagulation or no antiplatelet therapy were excluded.

The mean age of patients was 66.3 ± 11.6 years and 78% were men. Overall, 95.1% of patients had had a previous coronary event (MI or revascularization) at a median 4 years.

How DAPT
Patients Differ

The cohort was divided into those who on entry
were receiving either a single antiplatelet agent (n = 2,047 on aspirin and n =
776 on clopidogrel) or DAPT (n = 868).

On multivariate analysis, factors associated
with long-term DAPT use were:

Younger age

Persistent angina at inclusion

Higher BMI

MI 1 to 3 years prior

Multivessel CAD

Prior DES implantation

Prior CABG

Prior aortic or peripheral intervention

Lower LVEF

Over a 2-year follow-up period, the composite
of cardiovascular death, MI, or stroke (primary endpoint) occurred in 4.8% of
patients, and 0.8% experienced a bleeding event defined as Bleeding Academic
Research Consortium (BARC) type 3 or higher. In particular, there were 192
deaths (71 from cardiovascular causes), 86 MIs, and 34 strokes.

No difference was seen between the single and
dual antiplatelet therapy groups for the primary composite endpoint or the
individual endpoints with the exception of MI, which was higher in the DAPT
group (table 1).

Table 1.
Two-Year Outcomes

Single Agent(n =
2,798)

DAPT(n =
861)

P
Value

CV
Death, MI, or Stroke

4.6%

5.5%

.301

CV Death

2.0%

1.6%

.465

MI

2.0%

3.4%

.026

Stroke

1.0%

0.7%

.423

BARC ≥
3 Bleeding

0.8%

1.1%

.396

After propensity-score matching, the 2 groups
(n = 824 each) had similar rates of all endpoints, with the composite endpoint
and bleeding rising steadily over the study period. The results were consistent
across multiple subgroups.

The authors say the study reflects “a contemporary
management of CAD patients,” and comment that “the proportion of patients on
DAPT (24%) was relatively high despite no clear recommendation for such a
prescription in stable patients.”

Dr. Lemesle and colleagues say that although
the results do not support use of long-term DAPT in this cohort, “very
high-risk patients with anatomical particularities (including multiple or very
long stenting, left main stenting) or history of previous [stent thrombosis]
for example may still benefit” from such therapy. Moreover, the strategy
appears to be safe provided patients are thoroughly assessed for bleeding risk.
However, they add, this approach should be the exception rather than the rule.

A
Rationale for Prolonged DAPT in the Absence of Randomized Support

In a telephone interview with TCTMD, Sorin J.
Brener, MD, of Weill Cornell Medical College (New York, NY), said the
prevalence of DAPT use in stable patients in CORONOR is probably in line with
US practice.

The randomized CHARISMA trial, which
overall found DAPT no more effective than aspirin in preventing ischemic events
after a median 28 months, was “either neutral or positive, depending on how you
look at it,” he said, “but certainly patients who had symptomatic disease did
better with DAPT than single antiplatelet therapy.”

One important—and unfortunate—difference
between CHARISMA and the registry study, he noted, is the median interval from
initial event to enrollment (about 1 year vs a median 4 years), marking CORONOR’s
population as clearly more stable. That factor may account for the low rate of
events in the latter study, he added.

Dr. Brener said he is among a minority of
physicians who maintain patients with established CAD on DAPT indefinitely if
they do not bleed and can afford the cost. “If you believe that DAPT passivates
the vessel, as I do, it potentially prevents future events. It’s not because of
any stents patients have, it’s because of their atherosclerosis,” he asserted.
Acknowledging that the practice is not sanctioned by guidelines, he said he
tells patients, “We’re not sure [DAPT] helps, but if you tolerate it well, then
it makes sense to keep you on it.”

The current study reinforces the need for
randomized trials to assess the usefulness of prolonged DAPT, either with
clopidogrel or newer thienopyridines, Dr. Brener said. The large DAPT trial, in
which 1 arm received the therapy for up to 30 months past DES implantation,
will report results by the end of the year, he noted.

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